1. Field of the Invention
The present invention provides antibodies that immunospecifically bind to a galanin peptide and compositions comprising said antibodies. The invention also provides prophylactic and therapeutic protocols to prevent, treat, manage, and/or ameliorate disorders associated with aberrant expression and/or activity of galanin and/or a galanin receptor, including, without limitation hyperproliferative disorders, Alzheimer's disease, depression and eating disorders, or one or more symptoms thereof, said protocols comprising the administration of antibodies that immunospecifically bind to a galanin peptide alone or in combination with other therapies. The invention also encompasses methods and compositions for diagnosing, monitoring, and prognosing hyperproliferative disorders. The present invention further relates to articles of manufacture and kits comprising antibodies that immunospecifically bind to a galanin peptide.
2. Background of the Invention
2.1 Cancer
Cancer is a leading cause of death in the world and lung cancer is one of the most common types. In the United States, 28% of all cancer deaths are due to lung cancer (Jomal et al, 2001, J. Natl. Cancer Inst. 93: 277-283). Thus, there is a critical need for improved cancer therapies, particularly for lung cancer. Prognosis of lung cancer patients is poor with a 5 year survival rate of 14% (Zochbauer-Muller et al. 2002, Annu. Rev. Physiol. 64: 681-708).
Although cancer is a diverse set of diseases there are certain features that are common to cancer cells. These include increased proliferation, resistance to apoptosis, resistance to anti-growth signals, and ability to metastasize (Hanahan and Weinberg, 2000 Cell 100: 57-70).
Cancer is a disease that is largely caused by somatic mutations, and it is thought that a cell must accumulate multiple genetic alterations to make the transition from a normal cell to a fully malignant cell (Hanahan and Weinberg, 2000, Cell 100: 57-70). Genes that promote cancer through increased activity caused by mutation or over-expression are known as oncogenes, while genes whose loss of function promotes cancer are referred to as tumor suppressors.
Gene amplifications are important genetic alterations in the development and progression of human cancers by increasing the expression of oncogenes (Pollack et al. 2002, Proc. Natl. Acad. Sci. (USA) 99: 12963-12968: Li et al, 2002, Nature Genetics 31, 133-134). Many known oncogenes are found to be amplified and identifying novel amplified genes in a tumor is an efficient method for oncogene discovery.
Currently, cancer therapy may involve surgery, chemotherapy, hormonal therapy and/or radiation treatment to eradicate neoplastic cells in a patient (see, for example, Stockdale, 1998, “Principles of Cancer Patient Management”, in Scientific American: Medicine, vol. 3, Rubenstein and Federman, eds., Chapter 12, Section IV). Recently, cancer therapy can also involve biological therapy or immunotherapy. All of these approaches pose significant drawbacks for the patient. Surgery, for example, may be contraindicated due to the health of the patient or may be unacceptable to the patient. Additionally, surgery may not completely remove the neoplastic tissue. Radiation therapy is only effective when the neoplastic tissue exhibits a higher sensitivity to radiation than normal tissue, and radiation therapy can also often elicit serious side effects. Hormonal therapy is rarely given as a single agent and although it can be effective, is often used to prevent or delay recurrence of cancer after other treatments have removed the majority of the cancer cells.
With respect to chemotherapy, there are a variety of chemotherapeutic agents available for treatment of cancer. Many cancer chemotherapeutics act by inhibiting DNA synthesis, either directly, or indirectly by inhibiting the biosynthesis of the deoxyribonucleotide triphosphate precursors, to prevent DNA replication and concomitant cell division (see, for example, Gilman et al., Goodman and Gilman's: The Pharmacological Basis of Therapeutics, Eighth Ed. (Pergamom Press, New York, 1990)). These agents, which include alkylating agents, such as nitrosourea, anti-metabolites, such as methotrexate and hydroxyurea, and other agents, such as etoposides, campathecins, bleomycin, doxorubicin, daunorubicin, etc., although not necessarily cell cycle specific, kill cells during S phase because of their effect on DNA replication. Other agents, specifically colchicine and the vinca alkaloids, such as vinblastine and vincristine, interfere with microtubule assembly resulting in mitotic arrest. Chemotherapy protocols generally involve administration of a combination of chemotherapeutic agents to increase the efficacy of treatment.
Despite the availability of a variety of chemotherapeutic agents, chemotherapy has many drawbacks (see, for example, Stockdale, 1998, “Principles Of Cancer Patient Management” in Scientific American Medicine, vol. 3, Rubenstein and Federman, eds., ch. 12, sect. 10). Almost all chemotherapeutic agents are toxic, and chemotherapy causes significant, and often dangerous, side effects, including severe nausea, bone marrow depression, immunosuppression, etc. Additionally, even with administration of combinations of chemotherapeutic agents, many tumor cells are resistant or develop resistance to the chemotherapeutic agents. In fact, those cells resistant to the particular chemotherapeutic agents used in the treatment protocol often prove to be resistant to other drugs, even those agents that act by mechanisms different from the mechanisms of action of the drugs used in the specific treatment; this phenomenon is termed pleiotropic drug or multidrug resistance. Thus, because of drug resistance, many cancers prove refractory to standard chemotherapeutic treatment protocols.
There is a significant need for alternative cancer treatments, particularly for treatment of cancer that has proved refractory to standard cancer treatments, such as surgery, radiation therapy, chemotherapy, and hormonal therapy. Further, it is uncommon for cancer to be treated by only one method. Thus, there is a need for development of new therapeutic agents for the treatment of cancer and new, more effective, therapy combinations for the treatment of cancer.
Biological therapies/immunotherapies such as monoclonal antibody therapies are becoming increasingly important as new therapeutics in a variety of diseases including cancer (Berger et al. 2002, Am J. Med. Sci. 324: 14-30). Widely used therapeutic antibodies include Rituxan (IDEC) for lymphoma and Herceptin (Genentech) for breast cancer (Dillman, 2001, Cancer Invest. 19: 833-841). Although biological therapies/immunotherapies may produce side effects such as rashes or swellings, flu-like symptoms, including fever, chills and fatigue, digestive tract problems or allergic reactions, in general they are better tolerated than conventional cancer chemotherapies. Therapeutic antibodies for use in the treatment are few in number and there is a need to identify more therapeutically useful targets for biological therapies.
2.2 Galanin and Galanin Receptors
Galanin is a 29- or 30-amino acid peptide suggested to play a role in pain processing, learning and memory, prolactin secretion and other biological processes. Several galanin receptor subtypes are present in dorsal root ganglia and spinal cord with a differential distribution. The galanin receptor type 1 (GALR1) is known to normally be expressed predominantly in basal forebrain, hypothalamus, as well as spinal cord. On the other hand, the galanin receptor type 2 (GALR2) has been found to normally be widely distributed in brain and is also present in the pituitary gland and peripheral tissues (Depczynski et al., 1998, Annals of the New York Academy of Sciences 863: 120-128). GALR2 has been found to initiate multiple signaling pathways in small cell lung cancer cells by coupling to G(q), G(i) and G(12) proteins (Wittau et al., 2000, Oncogene 19(37): 4199-209). The galanin receptor type 3 (GALR3) has been found to normally be expressed in the periphery and at the lower levels of the central nervous system.
Amplification is an important means of increasing gene expression in tumor cells and many known oncogenes are over-replicated in cancer cells. It has been previously discovered that the genes encoding galanin and two of its receptors, GALR2 and GALR3, are amplified in lung cancer (Mu and Powers, International Publication No. WO 03/018770). Galanin is amplified in greater than 50% of lung cancer samples. Strikingly, the genes encoding GALR2 and/or GALR3 are frequently co-amplified with galanin. Since the three genes are located on different chromosomes, their co-amplification provides compelling genetic evidence that the activity of this pathway is being selected for its role in the establishment and progression of lung cancer. The genes encoding galanin and its receptors are over-expressed at a higher frequency than they are amplified indicating that other mechanisms in addition to DNA copy number changes can regulate expression of these genes. In addition to lung cancer, the genes encoding galanin, GALR2 and GALR3 were found to be amplified and/or over-expressed in several other cancers including breast, prostate, stomach, esophagus, bladder, liver, melanoma, and lymphoma.
2.3. Antibodies
The use of antibodies to block the activity of foreign and/or endogenous polypeptides provides an effective and selective strategy for treating the underlying cause of disease. Naturally occurring antibodies (immunoglobulins) have two heavy chains linked together by disulfide bonds and two light chains, one light chain being linked to each of the heavy chains by disulfide bonds. Each heavy chain has at one end a variable domain (VH) followed by a number of constant domains. Each light chain has a variable domain (VL) at one end and a constant domain at its other end; the constant domain of the light chain is aligned with the first constant domain of the heavy chain, and the light chain variable domain is aligned with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light and heavy chain variable domains, see e.g. Chothia et al., J. Mol. Biol. 186:651-663 (1985).
The variable domains of each pair of light and heavy chains are involved directly in binding the antibody to the antigen, whereas the constant domains are not involved directly in the antibody-antigen binding, but are involved in various effector functions, such as participation of the antibody in antibody-dependent cellular cytotoxicity. Each domain of natural light and heavy chains contains four framework (FR) regions, whose sequences are somewhat conserved, connected by three hyper-variable regions called Complementarity Determining Regions (CDRs) (see Kabat, E. A. et al., Sequences of Proteins of Immunological Interest, National Institutes of Health, Bethesda, Md., (1987)). The four framework regions largely adopt a β-sheet conformation and the CDRs form loops connecting, and in some cases forming part of, the β-sheet structure. Thus, the antigen binding site is formed by the CDRs in each chain that are held in close proximity by the framework regions, together with the CDRs from the other chain.
The discovery of monoclonal antibody technology in the mid-1970's heralded a new age of medicine. Unfortunately, the development of therapeutic products based on monoclonal antibodies has been severely hindered by a host of drawbacks inherent in antibody production. Since most monoclonal antibodies are rodent-derived, they do not fix human complement well and they are frequently antigenic in human clinical use. For example, a major limitation in the clinical use of rodent monoclonal antibodies is an anti-globulin response during therapy (Miller, R. A. et al., Blood 62:988-995 (1983); Schroff, R. W. et al., Cancer Res. 45:879-885 (1985)). A number of studies have shown that after injection of a foreign immunoglobulin, the immune response in a patient's body can be quite strong, essentially eliminating the antibody's therapeutic utility after an initial treatment.
The production of “chimeric” antibodies in which an animal antigen-binding variable domain is coupled to a human constant domain has proven somewhat successful (Morrison, S. L. et al., Proc. Natl. Acad. Sci. USA 81:6851-6855 (1984); Boulianne, G. L. et al., Nature 312:643-646 (1984); Neuberger, M. S. et al., Nature 314:268-270 (1985)), however, significant immunogencity problems remained. For example, in the case of the murine anti-CD3 antibody, OKT3, much of the resulting anti-globulin response is directed against the variable region rather than the constant region (Jaffers, G. J. et al., Transplantation 41:572-578 (1986)).
More recently, recombinant DNA technology has been employed to produce immunoglobulins which have human framework regions combined with CDRs from a donor mouse or rat immunoglobulins (See Jones, P. T. et al., Nature 321:522-525 (1986); Riechmann, L. et al., Nature 332:323-327 (1988); Verhoeyen, M. et al., Science 239:1534-1536 (1988)). In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.
A major problem with humanization procedures has been a loss of affinity for the antigen (Jones, P. T. et al., Nature 321:522-525 (1986)), in some cases as much as 10-fold or more. In some instances, substituting CDRs from rodent antibodies for the human CDRs in human frameworks was sufficient to transfer high antigen binding affinity (Verhoeyen, M. et al., Science 239:1534-1536 (1988)), whereas in other cases it has been necessary to additionally replace one (Riechmann, L. et al., Nature 332:323-327 (1988)) or several (Queen, C. et al., Proc. Natl. Acad. Sci. USA 86:10029-10033 (1989)) framework region residues. A number of FR residues have been suggested as critically affecting the conformation of particular CDRs and thus their contribution to antigen binding (Chothia, C. & Lesk, A. M., J. Mol. Biol. 196:901-917 (1987); Chothia, C. et al., Nature 342:877-883 (1989); Tramontano, A. et al., J. Mol. Biol. 215:175-182 (1990); Margolies et al., Proc. Natl. Acad. Sci. USA 72:2180-2184 (1975)). Furthermore, it is known that the function of an antibody is dependent on its three-dimensional structure, and that amino acid substitutions can change the three-dimensional structure of an antibody. It has previously been shown that the antigen binding affinity of a humanized antibody can be increased by mutagenesis based upon molecular modeling (Riechmann, L. et al., Nature 332:323-327 (1988); Queen, C. et al., Proc. Natl. Acad. Sci. USA 86:10029-10033 (1989)).
Thus, there is a need to provide antibodies that specifically bind to a galanin peptide (for example, a human galanin) for treatment of various types of cancer where the genes encoding galanin and its receptors are amplified and/or overexpressed. There is a need to provide humanized immunoglobulins that bind a galanin peptide with strong affinity and thereby inhibit binding of galanin to its receptors. These humanized antibodies should be substantially non-immunogenic in humans, and be easily and economically produced in a manner suitable for therapeutic formulation and other uses.
Citation or discussion of a reference herein shall not be construed as an admission that such is prior art to the present invention.